Question about a Salary Increase

I'm currently negotiating a pay raise as a full-time employee. I figured it's a good thing to have my pay increase/new salary in writing or on the contract somewhere.

How would this happen normally? Would I get a new contract with the pay stated, or would an email suffice, or should I ask for some other document?

Thanks and happy new year!

edit: added the full-time employee part.

by thefirefistace